Low-Aspect Antenna Using High Permeability Ring Resonator
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Solution Overview
Problem
Existing antennas with low aspect ratios face performance limitations in terms of bandwidth and efficiency while maintaining radiation or sensitivity patterns perpendicular to the mounting surface, as reducing height degrades their performance.
Innovation Solution
A ring-shaped RF resonator with a height of no more than λ/50 and a material with an average relative magnetic permeability of at least 10, supporting a circulating magnetic current, which induces an electric dipole moment for vertically polarized radiation patterns, is used, along with a feed structure to couple RF energy effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the antenna height is reduced to minimize aerodynamic drag and visual signature, then the aspect ratio is improved, but the bandwidth and efficiency of the antenna deteriorate
Solution Approach 1:
The patent changes the fundamental operating parameters of the antenna by using high magnetic permeability materials (μr ≥ 10) to enable resonance at much lower heights (h ≤ λ/50) compared to conventional antennas. This parameter change allows the antenna to maintain acceptable bandwidth and efficiency while achieving a dramatically reduced aspect ratio, directly resolving the technical contradiction between low profile and performance.
Solution Approach 2:
The patent employs composite structures combining magnetic materials with high permeability (μr ≥ 10) and low loss tangents (tan δ ≤ 0.1) with conventional antenna elements. This composite approach enables the antenna to achieve both the reduced height requirement and maintain radiation performance, as the magnetic materials enhance the effective electrical length and resonance characteristics without increasing physical height.
2Shape
If the antenna height is reduced to conform to mounting surface shape, then the aesthetic appearance and aerodynamic performance are improved, but the radiation pattern quality deteriorates
Solution Approach 1:
By changing the material parameters (high μr, low tan δ) and operating parameters (resonance frequency, current distribution), the patent enables the antenna to maintain vertically polarized radiation patterns at heights of h ≤ λ/50. The magnetic materials allow the antenna to achieve electric dipole-like radiation characteristics despite the reduced height, preserving radiation pattern quality while conforming to the mounting surface.
3Ease of manufacture
If conventional antenna materials are used, then the manufacturing is simpler, but the bandwidth and efficiency are insufficient at very low heights
Solution Approach 1:
The patent specifies composite material structures combining magnetic materials with particular properties (μr ≥ 10, tan δ ≤ 0.1) with conventional antenna elements. This composite approach balances manufacturing feasibility with enhanced performance, as these magnetic materials are commercially available and can be integrated into existing antenna designs to achieve both ease of manufacture and improved bandwidth/efficiency at low heights.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design maintains good performance characteristics, including bandwidth and efficiency, even with a very small vertical height, achieving impedance matching and radiation efficiency over a significant frequency range, while minimizing aerodynamic drag and visual signature.
Implementation Method 1
The resonator has a height of no more than λ/50, and it has an electromagnetic resonance at the operating frequency.
Implementation Method 2
a ring-shaped radiofrequency (RF) resonator that defines a path for a circulating magnetic current
Implementation Method 3
a ring of material disposed transverse to the vertical dipole axis and having an average magnetic permeability more than ten times the magnetic permeability of air
Data Source
AI summary
An antenna comprises a ring-shaped radiofrequency resonator that defines a path for a circulating magnetic current. In an implementation, the resonator has a height of no more than 2% of an operating wavelength, and it has an electromagnetic resonance at the operating frequency. In an implementation, the antenna is of a type having a vertical, short electric dipole radiation or sensitivity pattern. It comprises, as the dominant radiative element, a ring of material disposed transverse to the vertical dipole axis and having an average magnetic permeability more than ten times the magnetic permeability of air. The ring has a maximum outer diameter and a height that is less than the maximum outer diameter. The antenna further includes a feed structure adapted to couple radiofrequency energy into and/or out of a magnetic current circulating in the ring.